Laura Speed
Superior Olfactory Language and Cognition in Odor Synaesthesia
Olfaction is often considered a vestigial sense in humans. This perspective is
reflected in how we think and talk about smells in the West, with odor imagery
and odor language reported to be difficult. In the present study we demonstrate
odor cognition is superior in odor synaesthesia, where there are additional
sensory connections to odor concepts. Synaesthesia is a neurological
phenomenon in which input in one modality leads to involuntary perceptual
associations. Semantic accounts of synaesthesia posit synaesthetic associations
are mediated by semantic activation of inducing concepts. Thus, synaesthetic
associations may strengthen conceptual representations. To test this idea, we ran
6 odor-color synaesthetes and matched controls on a battery of tasks exploring
odor and color cognition. Synaesthetes outperformed controls on tests of both
odor and color discrimination, demonstrating for the first time enhanced
perception in both the inducer (odor) and concurrent (color) modality. Thus,
synaesthetes not only experience additional perceptual experiences to nonsynaesthetes, but their primary perceptual experience is also different.
Synaesthetes were also more consistent and more accurate at naming odors than
controls. We propose synaesthetic associations to odors strengthen odor
concepts, making them more differentiated (facilitating odor discrimination) and
easier to link with lexical representations (facilitating odor naming).